Physiological parameter monitors have included a combination of a host monitoring device (host device) and a single or multiple peripheral sensing devices (peripheral device) which are connected to the host device. The peripheral device(s) usually includes a connector that attaches to the complimentary connector on the host device side. Once the peripheral device connector is coupled to the host device, the peripheral device function is activated by the host monitoring device. Unfortunately, with such a connection configuration, the host monitor may not be able to tell whether a proper peripheral device is attached. As a consequence, an improper peripheral device can be plugged into the host monitoring device (assuming the physical shapes of the respective connectors allow for such mating) and the host monitor may be programmed by the user as if the intended peripheral device was connected. Likewise, the peripheral device may not be able to distinguish whether the host monitor attached to it is intended for proper coupling. As a consequence, the peripheral sensing device can be connected with the incorrect host monitoring device and the incorrect host device may be programmed by the user as if the proper peripheral device was connected thereto.